Processed soybean and process for producing the same

ABSTRACT

A method of producing a processed soybean is provided, in which soybean can be decomposed into soybean single cells in a shorter treatment time than before. This method includes the step of performing an enzyme treatment to the soybean in the presence of water by use of, as the enzyme, at least one of cellulase and hemicellulase, and preferably the hemicellulase produced by Trichoderma sp., thereby decomposing the soybean into individual soybean single cells. By this enzyme treatment, it is possible to reduce the production cost, and improve the safety of quality of the processed soybean.

DESCRIPTION

1. Technical Field

The present invention relate to a method of producing a processedsoybean comprising the step of efficiently decomposing soybean into itssingle cells by use of an enzyme, and the processed soybean obtained bythe same method.

2. Background Art

Soybean is a nutritious food material richly containing vitamins andproteins of good quality as well as isoflavone, saponin and lecithin,which are believed to be effective to prevent adult diseases, menopausaldisorders and cancer. However, for practical applications in the fieldof foods, it has been indicated from the past that there are problemsthat kinds of cooking methods are limited due to a hard epidermal tissueof the soybean, and the above nutritious components are changed inquality or solved out during the cooking operation, so that contents ofthe nutritious components in the cooked foods decrease.

As disclosed in the PCT International Publication No. WO 01/10242, thepresent inventor found that the soybean can be decomposed into healthysingle cells of the soybean by an enzyme treatment using a pectinaseproduced by the genus Bacillus without mechanically crushing thesoybean. The thus obtained processed soybean liquid and powderremarkably have increased the application possibility of soybean in thefield of foods.

However, the above enzyme treatment still has plenty of room forimprovement in time needed for the treatment. That is, as the timeneeded for the enzyme treatment becomes longer, the possibility ofgeneration and propagation of various germs during the enzyme treatmentincreases. In addition, it leads to an increase in cost of the processedsoybean as the final product. Therefore, it is desired to produce theprocessed soybean in a shorter treatment time than before in order tosupply the processed soybean with the stability of quality at a moderateprice.

SUMMARY OF THE INVENTION

From the above viewpoints, a primary concern of the present invention isto provide a method of producing a processed soybean, which hasadvantages of shortening time needed for an enzyme treatment to reducethe production cost, and improve the safety of quality of the processedsoybean.

That is, the production method of the present invention is characterizedby comprising the step of performing an enzyme treatment to the soybeanin the presence of water by use of at least one of cellulase andhemicellulase, thereby decomposing the soybean into individual soybeansingle cells.

According to the present invention, it is possible to remarkably shortenthe enzyme treatment time needed to decompose the soybean into thesoybean single cells, as compared with a conventional enzyme treatmentusing a pectinase produced by microorganisms of the genus Bacillus. Inaddition, damages to cell walls and cell membranes of the decomposedsoybean single cells are negligibly small, and protein bodies and lipidbodies in the single cells are maintained in a healthy state. Therefore,the processed soybean has a quality at least equal to the processedsoybean obtained by the conventional enzyme treatment using thepectinase.

As the enzyme, it is preferred to use at least one of cellulase andhemicellulase produced by the genus of Trichoderma. In this case, sincethe enzyme treatment can be performed in the neutral region without a pHadjustment, it is possible to avoid that the processed soybean isacidulated. In addition, from the viewpoint of improving the uniformityof the enzyme treatment and providing the processed soybean with a highquality, it is particularly preferred to use the hemicellulase producedby the genus Trichoderma.

In addition, it is preferred that the present method further comprises aparticle-size adjusting step of mechanically pulverizing the processedsoybean such that protein bodies in the soybean single cells are notbroken or crushed. The processed soybean obtained through theparticle-size adjusting step is effective to prepare a soybeancontaining drink, and is characterized in that the protein bodies aremaintained in a healthy state, and an average particle size of theprocessed soybean is in a range of 0.3 μm to 1 μm. In this case, theprocessed soybean is easily dispersed uniformly in the drink withoutconsiderably increasing the soybean smell. In addition, once theprocessed soybean is dispersed in the drink, it is hard to deposit inthe drink. Therefore, there is a further advantage that the drinkbecomes easy to drink, and does not taste gritty. In the case ofperforming the particle-size adjusting step, it is preferred to use ahomogenizer.

Therefore, a further concern of the present invention is to provide aprocessed soybean liquid obtained by mechanically pulverizing a slurry,in which the soybean single cells are dispersed, such that the proteinbodies in the soybean single cells are not broken. This processedsoybean liquid is characterized in that the soybean components having anaverage particle size of 0.3 μm to 1 μm are dispersed therein.Furthermore, the present invention provides a processed soybean powderhaving an average particle size of 0.3 μm to 1 μm, which is obtained bymechanically pulverizing the slurry, in which the soybean single cellsare dispersed, such that the protein bodies in the soybean single cellsare not broken, and then drying a resultant product.

Additional features of the present invention and advantages broughtthereby will be understood from the best mode for carrying out theinvention and preferred examples described below.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is an optical microscope photograph of a processed soybean powderobtained by a production method according to an embodiment of thepresent invention.

DETAIL EXPLANATION OF THE INVENTION

A method of producing a processed soybean of the present invention andthe processed soybean obtained by the same method are explained below indetail.

The method of producing the processed soybean according to a preferredembodiment of the present invention comprises the steps of soakingsoybean in water for a required time period, sterilizing the soybean byheating in the presence of water, cooling the heated soybean at anenzyme treatment temperature, performing an enzyme treatment to thesoybean in the presence of water and at least one of cellulase andhemicellulase, and deactivating the enzyme after the enzyme treatment toobtain a processed soybean liquid. If necessary, this production methodmay comprise a step of drying the processed soybean liquid to obtain aprocessed soybean powder, and/or a particle-size adjusting step ofpulverizing the processed soybean such that protein bodies in thesoybean single cells are not broken. Each of these steps is explainedbelow in detail.

First, after a required amount of raw soybean is washed with water, thesoybean is soaked in water. This step is performed to supply asufficient amount of water into individual cells of the soybean, so thatthe enzyme treatment performed later becomes easy to proceed. Thesoaking time is not limited. For example, in the present invention usingat least one of cellulase and hemicellulase as the enzyme, the soybeancan be soaked in water at 50° C. for 1 to 2 hours. In addition, a wateramount used in the soaking step can be determined such that a ratio byvolume of water to soybean is in a range between 2:1 and 4:1. To moreefficiently perform the enzyme treatment, it is preferred to soak thesoybean in water containing the cellulase and/or hemicellulase used inthe subsequent enzyme treatment.

Next, the soybean is sterilized by heating in the presence of water.This step is performed to deactivate a function of lipoxygenase includedin the soybean, and soften an intercellular substance, so that theenzyme treatment performed later becomes easy to proceed. In addition,this step is useful for thermal denaturation of the soybean proteins, sothat the digestion and absorption of the soybean proteins in the humanbody can be improved. To stably achieve these purposes, it isparticularly preferred to steam the soybean at 120° C. for 5 to 10minutes by use of a pressure cooker.

After the steamed soybean is cooled at a predetermined temperature, theenzyme treatment is performed by adding water and at least one ofcellulase and hemicellulase. For example, it is preferred that thesteamed soybean is cooled at about 50 to 60° C., which is suitable forthe enzyme treatment. In addition, it is preferred to use the water usedin the soaking step described above in the enzyme treatment from theviewpoint of zero emission of preventing the occurrence of wastewater orwaste products as far as possible during the production of the processedsoybean. Furthermore, it is preferred that the additive amount of wateris determined such that a ratio by volume of water to soybean is in arange between 2:1 and 4:1. The enzyme treatment is preferably performedin the neutral region.

It is preferred to perform the enzyme treatment, for example, at 50° C.for 5 to 10 minutes, while preferably agitating. The most importantfeature of the present invention is to use at least one of cellulase andhemicellulase, and particularly cellulase and/or hemicellulase producedby Trichoderma sp. In this case, there is an advantage of remarkablyreducing the enzyme treatment time, as compared with a conventional caseof performing the enzyme treatment with a pectinase produced by thegenus Bacillus, while maintaining the quality of the processed soybeanin an equal level to the conventional case. By the reduction in enzymetreatment time, it is possible to effectively prevent the generation andpropagation of various germs during the production of the processedsoybean, and reduce the production cost.

Agitating is effective to further reduce the enzyme treatment time.However, excessive agitating should be avoided to prevent that thesoybean single cells are broken thereby. For example, it is preferred toselect a soft agitating condition of rotating a stirring wing at a speedof 20 to 200 rpm in the mixture. In this case, the soybean can beefficiently decomposed into soybean single cells by agitating, andsimultaneously the cellulase and/or hemicellulase can uniformly act onthe soybean cells. Therefore, a smooth enzyme treatment can be achieved.

In the enzyme treatment of the present invention, for example, it ispossible to use cellulase or hemicellulase produced by Aspergillus nigeror Trichoderma sp., and preferably the cellulase and/or hemicellulaseproduced by Trichoderma sp. from the viewpoint of easily controlling theenzyme treatment. That is, when using the cellulase or hemicellulaseproduced by Aspergillus niger, it is needed to place an environment ofthe enzyme treatment in an acid region by use of a pH adjuster.Therefore, there is a fear that the processed soybean is acidulated. Onthe other hand, when using the cellulase and/or hemicellulase producedby Trichoderma sp., the enzyme treatment can be performed in the neutralregion. In this case, it is not necessary to use the pH adjuster.Therefore, the processed soybean having good quality and taste can bestably obtained.

It is preferred that an additive amount of cellulase or hemicellulase isin a range of 0.01 to 1 wt %, and more preferably 0.05 to 0.5 wt % withrespect to a weight of the soybean measured before the soaking step.When using a mixture of cellulase and hemicellulase as the enzyme, atotal amount of them is preferably determined in the above range. Whenthe additive amount is less than 0.01 wt %, it may be difficult todecompose the soybean into the soybean single cells. In addition, thereis a tendency that the enzyme treatment time is prolonged. On the otherhand, more than 1 wt % of the enzyme may be used. However, a furtherreduction in the enzyme treatment time will not be obtained. On thecontrary, it will lead to an increase in production cost.

Thus, the soybean can be decomposed into the soybean single cells by theenzyme treatment of the present invention without breakage of thesoybean cells. A slurry, in which the thus obtained soybean single cellsare dispersed, is kept at 50° C. for 15 to 30 minutes for aging. At thistime, if necessary, the slurry may be agitated by the stirring wingrotated at a speed of about 20 to 30 rpm. The aging time can be reducedby agitating.

Next, a heat treatment is performed to the slurry to deactivate theenzyme action. For example, it is preferred to heat the slurry at about90 to 100° C. for 5 to 15 minutes.

A processed soybean powder can be obtained by drying the slurry, inwhich the obtained soybean single cells are dispersed, according to aflash drying method or a spray drying method. The flash drying method iseffective to quickly dry a muddy material to obtain a powder as a driedproduct, and characterized by providing the muddy material in a hotairflow having a high flow rate, and feeding the muddy material alongthe hot airflow. This drying method can be performed by use of aso-called flash dryer. In the present invention, for example, it ispreferred to select a drying condition of 120° C. and 5 seconds. Inaddition, when the spray drying method is selected, it is preferred touse a spray dryer.

By the production method described above, the processed soybean liquidand powder can be obtained. As an example, an optical microscopephotograph of the obtained processed soybean powder is shown in FIG. 1.It shows that damages to the cell walls and cell membranes of thesoybean single cells are negligibly small, and protein bodies and lipidbodies in the soybean cells are maintained in a healthy state. Inaddition, it shows that the soybean single cells are at least equal tothem of the processed soybean obtained by the enzyme treatment with thepectinase produced by the genus Bacillus, which is disclosed in the PCTInternational Publication No. WO 01/10242.

Preferred examples of foods containing the processed soybean liquid orpowder of the present invention comprises flour based foods such asspaghetti, macaroni and pasta, prepared meats such as Hamburg and meatballs, soybean foods such as soybean curd and soymilk yogurt,soybean-protein containing foods, breads such as baked roll, Hamburgerbun and English muffin, cream, soy paste, vegetarian cheese, cereal,biscuit, cracker, dressing, healthy foods, diet foods such as konnyakujelly, bean jam, pudding, cream, jam, curry, ice cream, sherbet, andsweets. In addition, preferred examples of a drink containing theprocessed soybean of the present invention comprises fruit juices,vegetable juices such as carrot juice and tomato juice, coffee, soymilk,and soups such as miso soup and potage soup.

By the way, when the soybean containing drink is prepared by theaddition of the processed soybean powder or liquid obtained by theabove-described production method, it may difficult to uniformlydisperse the soybean single cells having an average particle size ofseveral microns in the drink. In addition, even when the soybean singlecells are uniformly dispersed in the drink by shaking a vessel with thesoybean containing drink therein, there is a fear that the soybeansingle cells are immediately deposited. Such an inconvenience easilyhappens in a drink having a relatively low viscosity such as coffee andlemon juice, as compared with the drink having a high viscosity such astomato juice and potage soup.

From the viewpoint of providing the soybean containing drink that hasgood taste and is easy to drink, it is preferred to further perform aparticle-size adjusting step of mechanically pulverizing the slurry, inwhich the soybean single cells are dispersed, such that the proteinbodies in the soybean single cells are not broken. In this case, it isimportant to perform the pulverizing step such that the soybean proteinbodies are maintained in a healthy state after the pulverizing step, andan average particle size of the soybean components after the pulverizingstep is in a range of 0.3 μm and 1 μm. That is, on the condition thatthe protein bodies are maintained in the healthy state, the cell wallsof the soybean single cells may be partially damaged.

With respect to the average particle size, when it is smaller than 0.3μm, damages to the protein bodies occur, so that the soybean smellgradually increases. Therefore, the advantages of the soybean singlecells may be lost by the particle-size adjusting step. On the otherhand, when the average particle size is larger than 1 μm, the effect ofpreventing the deposition in the drink may not be sufficiently obtained,so that the soybean containing drink tastes gritty and is not easy todrink. When performing the particle-size adjusting step, it is preferredto use a homogenizer. In this case, since composite actions of shearing,collision, cavitation and so on instantaneously happen in the slurry bya combination of plunger pump and valve, a uniform emulsion state can beobtained without the occurrence of flotage and deposition. When usingthe homogenizer in the particle-size adjusting step, it is preferred toselect a two-stage method comprising a first stage performed at atemperature of 50 to 60°C. under a pressure of 30 to 50 kg/cm², and thena second stage performed under a pressure of 150 to 200 kg/cm². In thiscase, there is an advantage that the average particle size satisfyingthe above range can be stably obtained.

In the present invention, it is essential to use at least one ofcellulase and hemicellulase. However, if necessary, the pectinaseproduced by microorganisms of the genus Bacillus or the other enzyme maybe supplementarily used.

EXAMPLES

The present invention is specifically explained according to thepreferred Examples.

Example 1

Raw soybean was washed water, and then soaked in water at 50° C. for 60minutes. At this time, a ratio by volume of water to soybean is 4:1.During the soaking step, 0.1% of hemicellulase produced by Trichodermasp. with respect to a weight of dried soybean was added to the water.After the soybean was removed (dewatered) from the water used in thesoaking step, the soybean was sterilized by heating at 120° C. for 5minutes. Next, the water containing the enzyme, which was collected atthe dewatering step, was added again to the soybean. An enzyme treatmentwas performed at 50° C. for 5 minutes under an agitating condition ofrotating a stirring wing at 200 rpm.

When the soybean is soaked in water, the epidermal layer of the soybeanis still hard. Therefore, the enzyme treatment slightly proceeds towardthe interior of the soybean. On the other hand, after the soybean issterilized by heating, the epidermal layer of the raw soybean issoftened. Therefore, the enzyme treatment can efficiently proceed towardthe interior of the soybean. Next, the rotation speed of the stirringwing was changed to 20 rpm. After a resultant mixture was left at 50° C.for 15 minutes for aging, it was heated and kept at 95° C. for 5 minutesto deactivate the enzyme function. A resultant slurry, in which soybeansingle cells are dispersed, was dried by means of a spray dryer toobtain a processed soybean powder, which contains the soybean singlecells individually decomposed in the healthy state, as shown in FIG. 1.

In the present Example, by using the hemicellulase produced byTrichoderma sp. as the enzyme, only 5 minutes are needed to complete thestep of decomposing the soybean into the soybean single cells at 50° C.This treatment time is much shorter than before. This effect can beeasily understood from a comparative example performed under the sameconditions except for using a pectinase produced by the genus Bacillusas the enzyme.

That is, when the enzyme treatment was performed at 50° C. for 5 minutesby use of the pectinase, soybean cells were separated from each otheronly in the vicinity of the soybean's surface. However, the enzymetreatment hardly proceeded at a core region of the respective soybean,so that the soybean cells of the core region were still being connectedto each other. To investigate the enzyme treatment effect with respectto time, the treatment time was extended. That is, additional enzymetreatments were performed for 10 min, 20 min, 30 min, 60 min and 90 min.As a result, to obtain the processed soybean power equal to that ofExample 1, it was needed to perform the enzyme treatment with thepectinase at 50° C. for at least 60 min. In the processed soybeanobtained by this enzyme treatment, it was observed that some of thesoybean was incompletely decomposed into the soybean single cells. Fromresults of a supplemental experiment, to uniformly decompose the soybeaninto the single cells, for example, it was effective to modify thecondition of the pretreatment, i.e., soak the raw soybean in water foran extended time of 24 hours prior to the enzyme treatment. Theextension of the soaking time leads to a reduction in productionefficiency of the processed soybean. Therefore, to keep a constantproduction efficiency, for example, an equipment investment ofincreasing the number of tanks for the soaking step will be needed.Thus, according to the production method of the present invention, it ispossible to reduce the soaking time as well as the enzyme treatmenttime, and save the cost for production equipments.

Thus, in the case of using the enzyme treatment condition of Example 1,the treatment time of the enzyme treatment with the hemicellulaseproduced by Trichoderma sp. can be reduced to at least sixth part of thetreatment time of the enzyme treatment with the pectinase produced bythe genus Bacillus. In addition, the time for the soaking step performedprior to the enzyme treatment can be also reduced. Moreover, theobtained processed soybean has no soybean smell and acid taste. Feelingof eating and appearance of the processed soybean are substantiallyequal to them of the processed soybean obtained by performing the enzymetreatment with the pectinase produced by the genus Bacillus for theextended time period.

Example 2

In place of the hemicellulase, soybean was decomposed into soybeansingle cells under the substantially same conditions of Example 1 exceptfor using cellulase produced by Trichoderma sp. as the enzyme. In thiscase, the soybean was decomposed into the soybean single cells byperforming the enzyme treatment at 50° C. for 1 minute under theagitating condition of rotating the stirring wing at 200 rpm. When usingthe cellulase, it is possible to further reduce the enzyme treatmenttime as compared with the case of using the hemicellulase. However, whenthe enzyme treatment is excessively continued, damages to cell walls ofthe obtained soybean single cells may occur. Therefore, it is needed tocarefully control the enzyme treatment time to prevent the damages. Inaddition, when the enzyme treatment is performed by use of a largevessel, there is a possibility of causing variations in treatment speedin the large vessel. Therefore, it is needed to well understand theprogress of the enzyme treatment in the large vessel to stably obtainthe soybean single cells with uniform quality.

By the way, the present Example using the cellulase produced byTrichoderma sp. presents the advantage of reducing the enzyme treatmenttime, as compared with the case of using the pectinase produced by thegenus Bacillus. However, from a comprehensive perspective, it ispreferred to use the hemicellulase produced by Trichoderma sp. Thetreatment speed in the case of using the hemicellulase is slightlyslower than that in the case of using the cellulase. However, since theenzyme treatment uniformly proceeds, the quality of the obtained soybeansingle cells can be easily stabilized. In other words, there is anadvantage that the enzyme treatment is easy to control in a remarkablyreduced treatment time, as compared with the case of using the pectinaseproduced by the genus Bacillus.

Example 3

A soybean containing drink that is easy to drink and tastes good wasproduced by use of a slurry, in which soybean single cells obtained inExample 1 are dispersed. First, a processed soybean puree was preparedby performing a particle-size adjusting step with use of a homogenizer.The particle-size adjusting step of this Example is composed of twostages. That is, a first stage was performed under the condition of 60°C. and 40 kg/cm², and then a second stage was performed under thecondition of 180 kg/cm². As a result, an average particle size of thesoybean single cells was reduced from several μm measured before theparticle-size adjusting step to about 0.8 μm measured after theparticle-size adjusting step. In addition, it was observed with amicroscope that although a certain level of damage to the cell walls ofthe soybean single cells was caused by the particle-size adjusting step,soybean protein bodies having an average particle size of about 0.3 μmare still maintained in a healthy state. Thus, since the damages to thesoybean protein bodies are negligibly small, the occurrence of soybeansmell was not realized after the particle-size adjusting step.

By use of the obtained processed soybean puree, a coffee drink, soybeansoup, and an orange juice were prepared under the following conditions.Taste and a degree of easy-to-drink of them were evaluated.

-   1) Coffee drink

The coffee drink was prepared by mixing 9.75 g of coffee, 24.5 g ofsugar, 9.55 g of the processed soybean puree, and required amounts ofglucose, milk powder, baking soda and water, while agitatingsufficiently.

-   2) Soybean soup

The soybean soup was prepared by adding a dried chip of a commerciallyavailable consomme soup to 300 g of the processed soybean puree (soybeansolid content: 20%), and then dissolving a resultant mixture with arequired amount of hot water.

-   3) Soybean containing fruit juice

The soybean containing fruit juice was prepared by drying the processedsoybean puree by use of a spray dryer to obtain a processed soybeanpowder, adding an orange juice to the processed soybean powder, and thensufficiently agitating a resultant mixture. A mixture ratio (wt %) ofthe processed soybean powder and the orange juice is 5:95.

-   4) Soybean containing vegetable juices

The soybean containing vegetable juices were prepared by drying theprocessed soybean puree by use of a spray dryer to obtain a processedsoybean powder, adding the processed soybean powder to each of a carrotjuice, tomato juice and a vegetable juice, which are commerciallyavailable, and then sufficiently agitating a resultant mixture by use ofa mixer for home use. A mixture ratio (wt %) of the processed soybeanpowder and each of the juices is 5:95.

In addition, comparative drinks were produced according to the samemethods described above except for using a soybean slurry, in whichsoybean single cells are dispersed, prepared without the particle-sizeadjusting step. Due to a deposition of the soybean single cells, thecomparative drinks were hard to drink, and tastes gritty. On the otherhand, the drinks of this Example were easy to drink without leavinggritty feeling on the tongue. In addition, the deposition of the soybeancomponents was negligibly small until each of the drinks was finished.In addition, the occurrence of soybean smell was not realized, as in thecase of the comparative drinks. Thus, it was confirmed that theparticle-size adjusting step is very effective to prepare the drinkscontaining the processed soybean of the present invention.

Example 4

In this Example, a nutrition enhanced soybean curd was produced by useof a processed soybean powder, which was obtained by drying theprocessed soybean puree of Example 3 by a spray dryer. That is, agelatin plate was firstly soaked in water. The gelatin was then added toabout 50 cc of a cow milk, while the cow milk bein heated in a smallpan, so that the gelatin was dissolved in the cow milk. After theheating is stopped, required amounts of the cow milk and the processedsoybean powder were added, and then uniformly mixed. A resultant mixturewas put in a wetted mold, and then cooled and solidified in arefrigerator to obtain the soybean curd of this Example. There was nodifference in taste and appearance between the obtained soybean curd anda comparative soybean curd prepared without using the soybean processedpowder.

However, a content of isoflavone in the soybean curd of this Example isabout 9 times as much as the conventional soybean curd, and a content ofdietary fiber in the soybean curd of this Example is about 15 times asmuch as the conventional soybean curd. In the conventional method ofproducing the soybean curd, the epidermis and the embryonic axis ofsoybean are generally removed. On the other hand, the processed soybeanof the present invention basically maintains the original proportion ofnutritions in raw soybean. Therefore, the dietary fiber richly includedin the epidermis of the soybean and the isoflavone richly included inthe embryonic axis of the soybean can be efficiently left in the soybeancurd. From these reasons, it is believed that the nutritions of thesoybean curd can be enhanced.

Example 5

In this Example, a noodle was produced by use of the processed soybeanpowder of Example 1. An additive amount of the processed soybean powderis 6% with respect to a total amount of raw powder components includingwheat flour. The thus obtained noodle has good feelings of eating. Inaddition, the occurrence of soybean smell was not realized at the timesof making and eating the noodle. Thus, a nutrition-enhanced noodle canbe obtained by use of the processed soybean of the present invention.

Example 6

In this Example, a bread was produced by use of the processed soybeanpowder of Example 1. First, as listed in Table 1, measured amounts ofraw materials were mixed for a required time at a kneading temperatureof 28° C. to obtain a dough. This dough was fermented for 100 minutes,and then divided into desired amounts. After the elapse of apredetermined bench time, they were baked under the condition of furnacetemperature and humidity of 38° C. and 80%, and a keeping time of 40minutes to obtain the breads of the present Example.

The thus obtained breads were eat by 5 subjects to check the occurrenceof soybean smell. However, no subject realized the occurrence of soybeansmell. In addition, since the bread containing the processed soybeanpowder of the present invention possesses intracellular water “cellwater”, it has a greater moisture-retaining capability than theconventional bread not containing the processed soybean. Therefore, asoftly baked bread can be obtained. TABLE 1 Raw materials Additiveamounts (g) Strong wheat flour 100 Sugar 6 Salt 2 Yeast 2.7 Processedsoybean powder 10 Compound margarine 7 Water 75

Example 7

In this Example, a low-salt soybean paste was produced by use of asoybean processed powder obtained by drying the processed soybean pureeof Example 3 by a spray dryer. That is, 50 g of the processed soybeanpowder and 125 cc of water were added to 500 g of a commerciallyavailable soybean paste, and then a resultant mixture was sufficientlymixed to obtain the low-salt soybean paste of this Example. By uniformlymixing the processed soybean powder in the soybean paste, the saltamount per 1 g of the soybean paste is relatively reduced. Therefore, itis possible to provide the low-salt soybean paste, which has a mildtaste and is nutrition-enhanced by the processed soybean.

Example 8

In this Example, a soymilk like drink was produced by use of a soybeanprocessed powder obtained by drying the processed soybean puree ofExample 3 by a spray dryer. That is, the processed soybean powder wasadded to mineral water at a mixture ratio of 30 g to 100 g of themineral water, and then a resultant mixture was sufficiently mixed by amixer for home use to obtain the soymilk like drink of the presentExample. In this case, it is possible to provide the soymilk like drink,which is low in price and easy to swallow, despite such a large amountof the solid content in the drink.

INDUSTRIAL APPLICABILITY

Thus, in the method of producing the processed soybean of the presentinvention, since at least one of cellulase and hemicellulase, andparticularly the hemicellulase produced by Trichoderma sp. is used asthe enzyme, the enzyme treatment time can be remarkably reduced ascompared with the conventional case of using the pectinase produced bythe genus Bacillus. Therefore, there are advantages of reducing theproduction cost, and preventing the generation and propagation ofvarious germs to further improve the safety of quality of the processedsoybean. Moreover, the basic concept of the present invention is toprovide an ecologically friendly production method from the viewpoint ofzero emission of waste products at the time of producing the processedsoybean.

1. A method for producing a processed soybean comprising the steps ofperforming an enzyme treatment to soybean in the presence of water byuse of at least one of cellulase and hemicellulase, thereby decomposingsaid soybean into individual soybean single cells.
 2. The method as setforth in claim 1, wherein said enzyme treatment is performed by use ofat least one of cellulase and hemicellulase produced by Trichoderma sp.3. The method as set forth in claim 1, wherein said enzyme treatment isperformed by use of hemicellulase produced by Trichoderma sp.
 4. Themethod as set forth in claim 1, wherein an additive amount of said atleast one of cellulase and hemicellulase is in a range of 0.01 to 1% ofa weight of dried soybean.
 5. The method as set forth in claim 1,further comprising the step of mechanically pulverizing a slurryobtained by said enzyme treatment, in which said soybean single cellsare dispersed, such that protein bodies in said soybean single cells arenot broken.
 6. The method as set forth in claim 5, wherein saidmechanically pulverizing step is performed by use of a homogenizer.
 7. Aprocessed soybean powder having an average particle size of 0.3 μm to 1μm, which is obtained by mechanically pulverizing a slurry obtained bythe method as set forth in claim 1, in which said soybean single cellsare dispersed, such that protein bodies in said soybean single cells arenot broken, and then drying a resultant product.
 8. A processed soybeanliquid obtained by the method as set forth in claim 5, in which theprotein bodies are maintained in a healthy state, and soybean componentshaving an average particle size of 0.3 μm to 1 μm are dispersed.
 9. Aprocessed food produced by adding the processed soybean obtained by themethod as set forth in claim 1 to another food material.
 10. A drinkcontaining the processed soybean obtained by the method as set forth inclaim
 5. 11. A noodle containing the processed soybean obtained by themethod as set forth in claim
 1. 12. A bread containing the processedsoybean obtained by the method as set forth in claim
 1. 13. A soybeancurd containing the processed soybean obtained by the method as setforth in claim
 5. 14. A soybean paste containing the processed soybeanobtained by the method as set forth in claim 5.